Process for the manufacture of isatin-alpha-halides halogenated in the nucleus



Patented June 22, 1937 2&84523 PROCESS ISATIN- cc-HALIDE S THE NUCLEUS FOR THE MANUFACTURE OF HALOGENATED IN Eduard Kambli, Basel, Switzerland, assignor to the firm of Society of Chemical Industry in Basle, Basel, Switzerland No Drawing. Application March 26, 1934, Serial No. 717,535. In Switzerland April 8, 1933 5 Claims.

This invention relates to the manufacture of are: added 16 parts of bromine and the whole is isatin-a-halides which are halogenated in the nucleus by treating with an halogenating agent an isatin-a-halide of the general formula 11 O I ll G-hal u 4:6- or lt'l-dimethoxyor diethoxy-isatin, of

respect of the yield of the nuclear chlorinated isatin-a-halide are obtained when sulfuryl chloride is used as the. halogenating agent.

The following examples illustrate the invention, the parts being by weight:

Example 1' 19,1 parts of 4-methyl-7-methoxyisatin of the formula C O NH OCHa are converted into 4-methyl-7-methoxyisatinachloride by heating them for half-an-hour at 80-85" C. with 22 parts of phosphorus pentachloride in 600 parts of chlorobenzene. To the mass produced, after it has been cooled to 0 C., there heated in the course of 4-5 hours to 40 C.

The lmethyl 5 bromo-7-methoxyizatin-achloride of the formula OCHs thus formed can be obtained by evaporating the solution in a vacuum in the form of dark brown crystals sensitive to moisture.

In many cases an isolation of the nuclear halogenated isatin-uhalide is not necessary; the solution or suspension of the a-halide can be used directly; for example, in the manner usual in the production of indigoid dyestuffs by condensation of suitable components.

Example 2 19,1'parts of 4-methyl-7-methoxyisatin are converted into the 4-methyl-7-methoxyisatin-achloride by heating them at -85 C. with 22 parts of phosphorus pentachloride and 600 parts of chlorobenzene, to the cooled solution there are added, while stirring, 14 parts of sulfuryl chloride. The whole is then kept for 1 hour at (SO-65 C. At the end of this time the chlorination, which occurs with lively evolution of sulfur dioxide, is complete.

If the solvent is in greater part separated, for example by distillation in a vacuum, there is obtained a brown crystalline magma which consists of the 4-methyl-5-chloro-l-methoxyisatinu-ChlOIldB; by filtration and washing with some petroleum ether, the 4-methy1-5-chloro-7-methoxyisatin-a-chloride is isolated.

In like manner the a-halides of 4- or 6- or '7- methylisatin or of 4:7-dimethylisatin may be halogenated.

' Example 3 19,5 parts of 4-methyl-7-chlorisatin of the formula c 0 NH are converted into 4-methy1-7-chlorisatin-m chloride by stirring them for half-an-hour at -100 C. with 22 parts of phosphorus pentachloride and 500 parts of chlorobenzene. After it has cooled to about 50-55 C., the solution is mixed with 14 parts of sulfuryl chloride; after stirring for 2-3 hours at 60-65 C., the chlorination is complete.

By separating the greater part of the solvent,

for instance by distilling in a vacuum, there is produced a brown crystalline magma of -methyl- 5Z7dlC1110llSatiI1-oc-Ch101ldE of the formula wherein at least one y is a member of the group of substituents consisting of methyl, alkoxy and alkylmercapto, wherein the alkyl radical belongs to the lower aliphatic series, and a is a member of the group of substituents consisting of halogen, alkoxy and alkylmercapto, wherein the alkyl radical belongs to the lower aliphatic series, by subjecting the correspondingly-substituted isatin to the action of a halogenating agent whereby the said isatin-a-halide is formed, and then subjecting the resultant material to the action of a second lialogenating agent to effect nuclear halogenation.

2. A process for the production of nuclearhalogenated isatin-a-chlorides comprising first producing an isatin-a-chloride of the general formula wherein at least one y is a member of the group of substituents consisting of methyl, alkoxy and alkylmercapto, wherein the alkyl radical belongs to the lower aliphatic series, and z is a member of the group of substituents consisting of halogen, alkoxy and alkylmercapto, wherein the alkyl radical belongs to the lower aliphatic series, by subjecting the correspondingly-substituted isatin to the action of a chlorinating agent whereby the said isatin-u-chloride is formed, and then subjecting the resultant material to the action of a second halogenating agent to effect nuclear" halogenation.

3. A process for the production of nuclearchlorinated isatin-uchlorides comprising first producing an lSELtiIl-u-ChlOIld of the general formula wherein at least one 1 is a member of the group of substituents consisting of methyl, alkoxy and alkylmercapto, wherein the alkyl radical belongs to the lower aliphatic series, and z is a member of the group of substituents consisting of halogen, alkoxy and alkylmercapto, wherein the alkyl radical belongs to the lower aliphatic series, by subjecting the c0rrespondingly-substituted isatin to the action of a chlorinating agent whereby the said is-atin-a-chloride is formed, and then subjecting the resultant material to the action of a second chlorinating agent to effect nuclear chlorination.

4. A process for the production of nuclearchlorinated isatin-u-chlorides comprising first producing an isatin-a-chloride of the general formula wherein at least one 1/ is a member of the group of substituents consisting of methyl, alkoxy and alkylmercapto, wherein the alkyl radical belongs to the lower aliphatic series, and 2 is a member of the group of substituents consisting of halogen, alkoxy and alkylmercapto, wherein the alkyl radical belongs to the lower aliphatic series, by subjecting the correspondingly-substituted isatin to the action of phosphorus pentachloride whereby the said isatinxchloride is formed, and then subjecting the resultant solution to the action of a second chlorinating agent to effect nuclear chlorination.

5. Process for the manufacture of 4-methyl-5- chloro-7-meth0xyisatin-u-chloride, consisting in causing sulfuryl-chloride to react with 4-methyl- 7-methoxyisatin-a-chloride of the formula CH3 a) OOHQ 

